Excess sewage sludge produced in any municipal or industrial wastewater treatment plant becomes a serious problem due to its increasing amount. This increase is related to the improvement of ...treatment technologies, expansion of sewage systems and the development of new industrial plants. The implementation and development of new technologies related to the utilization of sewage sludge is currently based on treating it as a substrate. Construction is an industry branch where sewage sludge, as well as other waste materials, can be used. The use of sewage sludge in building materials eliminates some of the expensive and energy-intensive stages of utilization, and the final product obtained is often stable and safe. This is confirmed, among other research regarding strength properties, water resistance, frost resistance and heavy metal leaching, especially when the amount of sewage sludge in solidified samples is low. The main purpose of the article is to present the latest methods of using sewage sludge (dried, dehydrated, and raw) in building and construction materials. Methods of producing low-strength materials for landfilling purposes have also been described.
The stabilization of sewage sludge with binding additives improves the end product's durability compared to standard solutions (dewatering). The use of sludge in concrete and mortars mixes is usually associated with a reduction in their strength compared to mixtures without sludge. The binder in the mixture is responsible for the strength of concrete or mortar. Sintering sewage sludge to make ceramic products (bricks, tiles) and lightweight aggregates is a promising approach, but in comparison to other methods such solutions require more energy expenditure. Nevertheless, the obtained products are stable and their durability, while lower than that of the control samples, still qualifies them for applications in construction.
Due to the different physicochemical properties of sludge, the methods of its management should be designed separately. It is therefore difficult to select one general and the most optimal method of management of sludge in building materials, but on the basis of the presented review, the authors indicate that one of the best methods of management is sintering sewage sludge into lightweight aggregates.
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•Utilization methods of raw sewage sludge/biosolids in construction industry are described.•Physicochemical characteristics of excess sludge and mortars is presented.•Compressive strengths of construction materials with raw sewage sludge/biosolids addition are presented.•The comparison of each group of construction materials with sewage sludge or biosolids was made.•The best approach of use sewage sludge/biosolids in the construction industry was proposed.
Fly ash, generated during the combustion of coal for energy production, is an industrial by-product which is recognized as an environmental pollutant. Because of the environmental problems presented ...by the fly ash, considerable research has been undertaken on the subject worldwide. In this paper, the utilization of fly ash in construction, as a low-cost adsorbent for the removal of organic compounds, flue gas and metals, light weight aggregate, mine back fill, road sub-base, and zeolite synthesis is discussed. A considerable amount of research has been conducted using fly ash for adsorption of NO
x
, SO
x
, organic compounds, and mercury in air, dyes and other organic compounds in waters. It is found that fly ash is a promising adsorbent for the removal of various pollutants. The adsorption capacity of fly ash may be increased after chemical and physical activation. It was also found that fly ash has good potential for use in the construction industry. The conversion of fly ash into zeolites has many applications such as ion exchange, molecular sieves, and adsorbents. Converting fly ash into zeolites not only alleviates the disposal problem but also converts a waste material into a marketable commodity. Investigations also revealed that the unburned carbon component in fly ash plays an important role in its adsorption capacity. Future research in these areas is also discussed.
Nowadays, the principle of balanced development of the machine building industry and, at the same time, the preservation of the natural environment is fundamental in the modern world. The processes ...used in the technological cycles of machine building enterprises should be safe both for humans and for the natural environment. One of the types of chemical and thermal treatment of metal is the process of liquid carbonitration, which allows improving the exploitation properties of treated pieces. As a result of this technology, two types of waste are generated. For a toxicological evaluation of the waste of carbonitration process, two test cultures were chosen as model organisms: Daphnia magna and Scenedesmus quadrcauda. In the course of the study, it was found that wastes from the process of carbonitration in certain concentrations have an acute toxic effect and belong to the 3rd and 4th hazard classes.
Purpose
Projects often face delays and unnecessary use of time due to various factors and reasons, and hence suffer from unfavourable consequences. The purpose of this paper is to identify the ...universal delay factors from an intensive literature review, complemented by delay factors in major Norwegian construction projects based on empirical data.
Design/methodology/approach
The study in which this paper is based includes an intensive literature review, and semi-quantitative open survey questionnaires. This paper addresses frequency and type of delay factors in construction projects, in Norway based on the survey, and worldwide based on the previous studies.
Findings
From the study, the causes of delays facing the Norwegian construction industry are: poor planning and scheduling; slow/poor decision-making process; internal administrative procedures and bureaucracy within project organisations; resources shortage (human resources, machinery, equipment); poor communication and coordination between parties; slow quality inspection process of the completed work; design changes during construction/change orders; sponsor/owner/client lack of commitment and/or clear demands (goals and objectives); late/slow/incomplete/improper design; office issues; and users’ issues. And the top 10 universal delay factors are: design changes during construction/change orders; delays in payment of contractor(s); poor planning and scheduling; poor site management and supervision; incomplete or improper design; inadequate contractor experience/building methods and approaches; contractor’s financial difficulties; sponsor/owner/client’s financial difficulties; resources shortage (human resources, machinery, equipment); and poor labour productivity and shortage of skills.
Research limitations/implications
When it comes to the identification of delay factors in major Norwegian projects, the research is based on a sample of 202 respondents from an open survey questionnaire. It should be noted that analysing a large population of respondents that have been asked open questions can be challenging due to the vague findings it might lead to. Also, when it comes to the identification of the universal delay factors, there were different methods used by different authors, within different context. Similar future studies in Norway based on qualitative and quantitative methods will give better verification for the findings.
Practical implications
This paper has documented the critical delay factors/causes in Norway. The results of this study will help project managers, in Norway and elsewhere, to be aware and know about the potential causes of delay in their construction projects, which will help to identify the possible risks in the early phases of the project. Another practical implication is to make project managers and policy makers conscious that delays are quite universal, making it necessary to identify them as a first step.
Social implications
The identification of delays factors and causes can permit projects to implement mitigation actions to avoid delays, thus allowing delivering schools, hospitals and other necessary infrastructure on schedule or ahead of schedule to society.
Originality/value
This paper highlights most (almost all) of the studies in the literature, including to the study done in Norway, concerning the delay factors in construction projects and large construction projects in general. This wide review of relevant literature will save time other academicians from having to conduct similar studies. This study will assist both academic and professional experts providing more insight about the delay causes in large-scale construction projects.
Building Information Modeling (BIM) has been recognized as an emerging technological innovation which can help transform the construction industry and it has been adopted broadly in the field of ...built environment. Due to the rapid development of BIM research, various stakeholders require a state-of-the-art review of the BIM research and implementation. The purpose of this paper is to provide an objective and accurate summary of BIM knowledge using 1874 published BIM-related papers. The results show that 60 key research areas, such as information systems, 3D modeling, design and sustainability and 10 key research clusters, such as architecture design studio, building information and lean construction, are extremely important for the development of BIM knowledge. The results are useful for the identification of research clusters and topics in the BIM community. More importantly, these results can help highlight how BIM-related research evolves over time, thus greatly contributing to understanding the underlying structure of BIM. This study offers useful and new insights to summarize the status quo of BIM knowledge and can be used as a dynamic platform to integrate future BIM developments.
•A bibliometric analysis of 1874 BIM-related articles is conducted.•The top three research topics include information system, 3D/nD modeling, and design.•The top three research clusters include architectural design studio, building information, and lean construction.•Four pillars, including culture, technology, management, and theory are identified.
The authors have attempted to summarize the evolution of research in Construction Productivity (CP) through a Systematic Literature Review (SLR) from the papers published from 2006 to 2017. The ...methodology adopted for the study is to use the systematic literature review for selecting the papers published in a few selected major journals of construction, built environment, and construction management fields. A total of eight journals selected for the SLR and 101 papers have been selected using the keyword “Construction Productivity in the title or the Keywords”. The findings of the study conclude that the studies in CP are focused in seven main areas are industry-level studies, the study of factors/attributes, measurement techniques, simulation and models, equipment and technology, issues and problems associated with CP, and improvement techniques and proposed frameworks.
PurposeBuilding information modeling (BIM) is a process of creating an intelligent virtual model integrating project data from design to construction and operation. BIM models enhance the process of ...communicating the progress of construction to stakeholders and facilitate integrated project delivery, coordination and clash detection. However, barriers within the construction industry in Ethiopia has led to slow BIM adoption in the country. The aim of this paper is to identify perceived BIM barriers, provide a platform to quantify their importance and develop a regression model to link individual's personal/professional attributes to their perception of BIM barrier.Design/methodology/approachTo address the objectives of this research, an online survey was developed to collect feedback from construction professionals in Ethiopia on 20 major adoption barriers extracted from a thorough review of literature. Relative importance index and strength of consensus metric were employed to identify the significance of barriers. This was then succeeded by performing exploratory factor analysis to determine the major constructs of BIM barriers which was then used to develop a multivariate regression model linking respondents' personal attributes to their perception of BIM barrier.FindingsResults revealed the importance of project complexity and BIM maturity level in prioritizing barriers that are more relevant under various contexts. More specifically, results indicated the following study highlights: Project complexity led to higher perceived weights for lack of appropriate physical/cloud infrastructures, and a BIM standard. Higher levels of BIM maturity signified the importance of BIM internal issues such as liability, licensing and maintenance issues among other adoption barriers. Female participants tended not to consider intangibility of BIM benefits as a major barrier towards BIM adoption compared to male participants. Age of the participants turned out to be the least important factor in their prioritization of BIM perceived adoption barriers.Originality/valueWhile many research studies have explored BIM adoption barriers in various countries around the world, none to the best of the authors' knowledge have attempted to develop a model to highlight the impact of individuals' personal/professional attributes on their perception of adoption barriers within their community which can help with prioritizing the barriers that are deemed to be more important given the characteristics of the community under study. Our result indicated the importance of BIM maturity level and project complexity in prioritizing barriers associated with BIM adoption within Ethiopia's construction industry.
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•Current state of the art of PHAs synthesis.•Sustainable production of PHAs from renewable resources.•Conversion of wastes e.g., glycerol, agro-wastes to bio-based PHAs.•Utilization ...of PHAs towards environmental sustainability.•Applications of PHAs in various fields.
Polyhydroxyalkanoates (PHAs) belong to group of biopolymers that have in recent times received growing research interest as a result of being eco-friendly and close characteristics with petrochemical based plastics. Alternatives to utilization of synthetic plastics are being explored since synthetic plastics are non-recyclable and non-biodegradable in nature. One of the innovations of Green Chemistry is utilization of renewable feedstocks such as biomass to achieve sustainable development with future circular economy. Bio-based products are of great interest to sustainable development as a result of diminishing fossil fuel reserves and rising environmental concerns. This review summarizes the productions of PHAs from renewable feedstocks such as lignocellulose, crude glycerol, levulinic acid (LA), palm-oil mill effluents (POME) and waste oils. The production of bio-based polymers has become much more professional and differentiated in recent years. Presently, there are bio-based alternatives for practically every application, therefore, this review presents applications of PHA in bio-refinery, medical sectors, agriculture sector, construction industry, and in packaging industry. The cost analysis of PHA from renewable sources with commercially available ones and potential to attain circular economy were also stressed. The reasons for this shift are connected to the non-renewability of fossil-based resources, the deteriorating environmental impacts, and the lack of biodegradability of the petroleum-produced materials.
Occupational incidents and accidents are still commonplace in the contemporary workplace, despite increased understandings of safety.
This article aims to yield new insights into safety-related ...thinking, decisions and behaviours through the application of an institutional logics perspective.
Semi-structured interviews with twenty-two managers in a railroad construction and maintenance organisation were conducted, in which a variety of topics related to occupational safety and management were discussed.
The results illustrate that an institutional logics perspective provides useful insights into the different logics of the market, profession, and corporation in the occupational safety context. Furthermore, the results demonstrate contradictory viewpoints, so-called complexity, between these three logics and subsequent management approaches.
We demonstrate that viewing occupational safety through the lens of institutional logics leads to a better understanding of safety and reveals various rationales for safety attitudes and behaviours that otherwise may have been dismissed as irrational. Understanding and possessing the discourse of logics can help managers and safety professionals with analysis and prevention of accidents.
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